Rock-drilling machine.



G. ANDERSSON.

ROCK DRILLING MACHINE. APPLICATION FILED AUG.6; I918.

Patented Apr. 8,1919.

eusur mnasson, or STOCKHOLM, SWEDEN.

ROCK-DRILLING- MACHINE.

Specification of Letters Patent.

Patented Apr. 8,1919.

Application filed August 6, 1918. Serial No. 248,598.

To all whom it may concern:

Be it known that I, GUSTAF ANnnBssoN, a

citizen of the Kingdom of Sweden, residhole by means of water supplied through the hollow bit from a water conduit located outside the cylinder or the bit holder of the machine.

Such machines have generally heretofore been so constructed that the outer Water conduit is connected with a ni ple fastened to the bit holder and the axis or bore of which extends at right angles to the axis of the cylinder, while the portion of the conduit'situated near to the nipple and screwed into the same is parallel or about parallel with the axis of the cylinder. Owing to this arrangement of the water conduit and the nipple, the connection between the conduit and the bit holder is liable to bebroken or loosened on account of the blows of the piston or pistons transmitted to said connection.

The object of this invention is to prevent said inconveniences by such a construction of the connection between the water conduit and the bit holder that the blows of the piston, instead of loosening said connectlon, act to strengthen and maintain the same. This object is attained. by providing the end of the outer water conduit with a mouthpiece or any other equivalent outlet member tapering in the direction from the Working end of the bit and loosely inserted in-a correspondingly formed bore or recess in the bit holder 1n such manner that the longitudinal axis of the mouth iece and said bore or recess is parallel or a out parallel with the axis of the cylinder. By this arran ement the reactive forces generated by, t e blows of the piston will tend to force the mouth piece or the like to-close contact with thebore or recess o'frthe bitholdeli,

A preferred embodiment of the invention is illustrated in the accompanying drawing showing an axial section through the forepart of the cylinder and the bit holder of a pneumatic rock drillin machine to which the invention is applietf Referring to the drawing, de-r,-2 is the piston or hammer, 3 the anvil block located between the piston 2 and the bit 4, and 5 is the bit holder. The bit 4 is provided with a central bore 6 through which scavenging water is supplied to the bore-hole from a water conduit 7. The water passes to the bore 6 through a channel 8 formed in the anvil block 3 and extending from the center of the surface 9 thereof which bears against the bit to the cylindrical side-surface 10. At this surface the channel 8 opens into a cylindrical recess 11 cut in the bit holder 5. From the recess 11 a channel 12.leads to a bore or recess 13' passing through a projection 14 of the bit holder 5. Said bore or recess 13 tapers in the direction from the working end of the bit 4, and the longitudinal axis of the bore 13 is parallel or about parallel to the axis of the cylinder 1. Preferably, the recess 13 1 is the cylinis conical having the apex of the cone directed away from said end of the bit,

Loosely inserted in the bore 13 is a mouthpiece 15 connected with the water conduit 7, the outer side-surface of said mouth piece 15 being formed in strict accordance with the inner surface of the bore 13, so that the mouth piece, when forcibly driven into the bore, fits snugly and water-tight in the same. To this end the mouth piece is, preferably, formed with a conical outer surface corresponding to the inner conical surface of the bore 13, the strict accordance being obtained by grinding said surfaces together. The mouth piece 15 is provided with one or more transverse channels 16 openin into an annular recess 17 formed in the wa l of the bore 13 and communicatin with the channel 12.. Another lo'ngitudina? channel 18 connects the transverse channels 16 with the water conduit 7.

Packing rings 19 of leather or the like are inserted around the anvil block?) in annular recesses at each end of the recess 11 and prevent the water passing through the recess 11 fmnrentering the cylinder.'

It will appear from the above that the blows effected by the piston2against the anvil block 3 will be transmitted to the bit holder 5 and its projection 14 in such man ner thatthey tend to force said projection contact with each other, without causing any breaking of the connection between the water conduit and the machine.

. Having now particularly described and, ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is z 1. In a rock drilling machine, the combination of a hollow bit, a bit holder, means supplying scavenging water to the bore hole through the bit, a;passage formed in the bit holder and communicating with said water supplying means and the cavity of the'bit,

and a member connected with said water supplying means and inserted tightly in said passage, the side-face of said outlet member tapering in the direction from the working end of the bit. 1

2. In a rock drilling machine, the combination of a hollow bit, a bit holder, means supplying scavenging water to the bore hole through the bit, an anvil block located at the rear end of the bit, a passage formed in the said anvil block and the bit holder and communicating with said water supplying means and the cavity of the bit, and a member connected with said water supplying means and inserted tightly in said passage, the side-face of said outlet member tapering in the direction from the working end of the bit.

3. In a rock drilling machine, the combination of a hollow bit, a bit holder, means supplying scavenging Water to the bore hole through the bit, a conical passage formed in the bit holder and communicating with said water supplying means and the cavity of the bit, and a conical member connected with said water supplying means and inserted tightly in said passage, the apex of the conical suriiaces being directed away from the working end of the bit.

4. Ina rock drilling machine, the combination of a hollow bit, a bit holder, means supplying scavenging water to the bore hole through the bit, an anvil block located at the rear end of the bit, passages formed in said anvil block and the bit holder and communicating with said water supply means and the cavity of the bit, the passage in the bit holder being conical, and a conical outlet member connected with said water supply: ing means and inserted tightly in said conical passage, the apex of the conical surfaces being directed away from the working end of the bit.

In testimony whereof I have signed my name.

GUSTAF ANDERSSON. 

